STUDY OF A SPOKE CAVITY FOR LOW-BETA APPLICATIONS

Since a few years, intensive studies have been developed on SC cavities (for instance, spoke-type or re-entrant cavities) for their use as accelerating structures in the low energy part of high power proton or ions accelerators (typically from 5 to 100 MeV). Within the framework of the EURISOL (EURopean Isotope Separation On-Line) & XADS (eXperimental Accelerator Driven System) European accelerators projects, IPN Orsay decided to plan a R&D program on low-beta spoke-type cavities. In the major part of this paper, we report on the optimization of the geometry of a β=0.35, 2 gap spoke cavity, aiming at achieving good electromagnetic parameters (i.e. lowest Epk/Eacc and Bpk/Eacc). A mechanical study is also presented, as well as a preliminary design of a proton spoke Linac (12-85 MeV) composed of β=0.18 and β=0.35, 2 gap cavities.